TheMembersAdvantage - TheMembersAdvantage.com

I inquired into an ad I received through an email for TheMembersAdvantage.com that said I had to complete 6 offers from different companies in order to receive a $500 gift card to Target. I completed all six but only received credit for 4. I then had to provide a PDF file to show that I completed the 2 credit card offers, had the card activated, and made a purchase on each one. They verified the one with Discover card, which meant I only had 1 more to complete. The PDF file I sent showed proof of all this for the other credit card (Citi Bank) and that was my 6th and final offer to fulfill. They are not giving me credit for the Citi card that I opened the beginning of June, and give me the same answer back 'they are waiting for the affiliate to reply and I should hear back that week". They then close the ticket for me after it not being resolved. Bottom line is that they know it is the last offer to fulfill and do not want to complete their end of the offer of the $500 gift card. Is this whole thing a scam, or what can I do?

Thank you. Diane